Electron probe microanalysis of rare earth doped gallium nitride light emitters

2018 ◽  
pp. 555-558
Author(s):  
S Dalmasso ◽  
R W Martin ◽  
P R Edwards ◽  
K P O'Donnell ◽  
B Pipeleers ◽  
...  
Keyword(s):  
Rare Earth ◽  
Gallium Nitride ◽  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Light Emitters ◽  
Rare Earth Doped

scholarly journals Rare Earth Occurrences in Streams of Processing a Phosphate Ore

Minerals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 262 ◽  
Author(s):  
Xiaosheng Yang ◽  
Hannu Tapani Makkonen ◽  
Lassi Pakkanen
Keyword(s):  
Rare Earth ◽  
Sulfuric Acid ◽  
Phosphoric Acid ◽  
Rare Earth Elements ◽  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Phosphate Ore ◽  
Mineral Liberation ◽  
Efficient Recovery ◽  
Liberation Analysis

Rare earth elements (REEs) are defined as lanthanides with Y and Sc. Rare earth occurrences including the REE-bearing phases and their distributions, measured by rare earth oxides (REOs), in the streams of processing a phosphate ore were determined by using MLA, the mineral liberation analysis and EPMA, the electron probe microanalysis. The process includes an apatite ore beneficiation by flotation and further processing of the beneficiation concentrate with sulfuric acid. Twenty-six, sixty-two and twelve percent of the total REOs (TREO) contents from the ore end up in the products of beneficiation tailings, phosphogypsum (PG) and phosphoric acid, respectively. Apatite, allanite, monazite and pyrochlore are identified as REE-bearing minerals in the beneficiation process. In the beneficiation tailings, the REEs are mainly distributed in monazite (10.3% TREO), apatite (5.9% TREO), allanite (5.4% TREO) and pyrochlore (4.3% TREO). Gypsum, monazite, apatite and other REE-bearing phases were found to host REEs in the PG and the REEs distributions are 44.9% TREO in gypsum, 15.8% TREO in monazite, 0.6% TREO in apatite and 0.6% TREO in other REE-bearing phases. Perspectives on the efficient recovery of REEs from the beneficiation tailings and the PG are discussed.

Synthetic TRPO4 crystals as reference samples in the quantitative X-ray electron probe microanalysis of rare-earth elements

2011 ◽  
Vol 66 (9) ◽  
pp. 831-837 ◽  
Author(s):  
Yu. G. Lavrent’ev ◽  
I. M. Romanenko ◽  
M. P. Novikov ◽  
L. V. Usova ◽  
V. N. Korolyuk
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
X Ray ◽  
Reference Samples

Rare-earth element determination in minerals by electron-probe microanalysis: application of spectrum synthesis

1998 ◽  
Vol 62 (1) ◽  
pp. 1-8 ◽  
Author(s):  
S. J. B. Reed ◽  
A. Buckley
Keyword(s):  
Rare Earth ◽  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Distribution Patterns ◽  
Correction Factors ◽  
Relative Precision ◽  
Element Determination ◽  
X Ray ◽  
Background Measurement ◽  
Spectrum Synthesis

AbstractElectron-probe microanalysis (EPMA) is applicable to rare-earth elements (REE) in minerals with relatively high REE concentrations (e.g. hundreds of parts per million). However, given that each of the 14 REE has at least 12 X-ray lines in the L spectrum, finding peak-free regions for background measurement can be problematical. Also, measured peak intensities are liable to require correction for interferences. Hitherto, little attention has been paid to the optimisation of background offsets and the implications of the wide variation in REE distribution patterns in different minerals. The ‘Virtual WDS’ program, which enables complex multi-element spectra to be synthesised, has been used to refine the conditions used for different REE distributions. Choices include whether to use the Lβ1 rather than the Lα1 line, background offsets, and counting times for comparable relative precision. Correction factors for interferences affecting peak and background measurements have also been derived.

Extraction of Rare Earth from La–Ni Alloys by the Glass Slag Method

2003 ◽  
Vol 18 (12) ◽  
pp. 2814-2819 ◽  
Author(s):  
Tetsuji Saito ◽  
Hironori Sato ◽  
Tetsuichi Motegi
Keyword(s):  
Rare Earth ◽  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Oxide Phase ◽  
Chemical Analyses ◽  
X Ray Diffraction ◽  
X Ray ◽  
Boron Trioxide ◽  
Ni Alloys

The use of the glass slag method in the extraction of rare earth from La–Ni alloys was studied. X-ray diffraction and electron probe microanalysis studies revealed that the La–Ni alloys produced by the glass slag method using boron trioxide consisted of Ni and Ni3B phases. No La-containing phase such as the LaNi5 phase and the La oxide phase was found in the resultant alloys. The chemical analyses confirmed that the La content in the alloys produced by the glass slag method was very limited. However, the glass slag materials contained a large amount of lanthanum. The La in the La–Ni alloys was successfully extracted by the glass slag method using boron trioxide.

Multiple color capability from rare earth-doped gallium nitride

2001 ◽  
Vol 81 (1-3) ◽  
pp. 97-101 ◽  
Author(s):  
A.J. Steckl ◽  
J. Heikenfeld ◽  
D.S. Lee ◽  
M. Garter
Keyword(s):  
Rare Earth ◽  
Gallium Nitride ◽  
Rare Earth Doped

Nanocrystalline Rare Earth-doped Gallium Nitride Phosphor Powders

2005 ◽  
Vol 866 ◽  
Author(s):  
G.A. Hirata ◽  
J. Tao ◽  
P. Chen ◽  
K.C. Mishra ◽  
J. McKittrick
Keyword(s):  
Rare Earth ◽  
Gallium Nitride ◽  
High Purity ◽  
Photoelectron Spectroscopy ◽  
Single Phase ◽  
Luminescent Properties ◽  
Nanocrystalline Powder ◽  
Rare Earth Ion ◽  
Chemical Route ◽  
Rare Earth Doped

AbstractWe report on the fabrication and luminescent properties of rare earth-doped gallium nitride (GaN) phosphor powders. Single phase GaN and GaN:RE3+ powders were prepared by using a novel chemical route.In this work a new method for the synthesis of high purity, single phase doped GaN powders is reported. (Ga1-xREx)N powders are obtained by dissolving metal nitrates (Ga(NO3)3, (RE(NO3)3) in deionized water and an organic fuel (hydrazine) in order to form a gallium/RE amorphous/nanocrystalline powder. The RE-oxide powders are then reacted with heated ammonia at different temperatures and processing times producing GaN:RE phosphors. X-ray diffraction analysis showed that single phase GaN powders are formed. Preliminary results show (Ga0.95Eu0.05)N powders are luminescent, with the main emission occurring at 611 nm which is due to the 5Do→7F2 transitions in Eu3+. High-purity GaN powders are obtained according to Xray photoelectron spectroscopy (XPS) chemical analysis. Low-temperature cathodoluminescence and photoluminescence measurements indicate that the emission at λ=611 nm is originated from energy transfer from the host to the rare earth ion and to a direct excitation to the Eu3+ electronic levels.This method can be used to obtain red-luminescence GaN:Eu3+ and other rare earth (e.g. Er, Tb, Tm)-doped GaN powders to produce green and blue luminescence as well.

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